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Transformer help

Posted: Fri Apr 21, 2017 12:30 pm
by lukebarber
Hello guys,

I have 2006 CNC 3 axis Bridgeport/Harndinge EZ Vision Mill.

My machine is wired for 3 phase 460 volts.

2.0 KW
3.3 amps and 1.1 Spindle amps

My question,

I only have single phase 240 coming in the shop.

I also have a used SEW Eurodrive VFD. ... atalog.pdf

What kind of transformer do you guys recommend to boost the volts from 240 to 460? Installed before or after transformer?

Re: Transformer help

Posted: Fri Apr 21, 2017 1:32 pm
by cnsperf
I had to do something similar for my CK-21. I went single phase 230 to a rotary phase converter to create three phase 230 and then from that to an Acme transformer to create the 460 three phase power. Do a google search for Acme Transformers in Lumberton, NC. Call their engineering group and tell them the info and they can make sure you get the right equipment. They are very helpful.

Re: Transformer help

Posted: Sat Apr 22, 2017 3:18 am
by crazyman
I've always considered having 3 phase installed if I ever build a house. Less $$ to run the A/C and well pump.

Re: Transformer help

Posted: Fri Jul 07, 2017 10:24 pm
by j-c-c
What did you finally do? The VFD drive looks to me the Model #3 is not large enough and or borderline? I have never checked but do they make rotary step up convertors? I don't believe so. I also wonder how sensitive the CNC electronics are to use of a rotary converter. Is this a daily often used piece of equipment? May want to get a small 15KW? 3 Phase diesel genset that has 480 V capibility or iuse a transforner, or whatever size needed for facility emergency back up, and use that until a better solution presents itself.

Re: Transformer help

Posted: Fri Jul 07, 2017 11:02 pm
by BigBlocksOnTop2
Are the motors set up with low voltage wiring (dual voltage)? With 460 volts the current is 4.5 amps. With ''house voltage'' (usually 240 VAC) the current would be around 9 amps and that is not taxing. Now I'm not sure about CNC electronics, but as far as powering up, I would look into a rotary 3 phase converter (you have to have 3 phase). I made one from a 3 hp, 3 phase 230/ 460 VAC motor and several lighting capacitors years ago and wired it for low voltage. It works great and powers up 2 small lathes and 1 small mill. Three phase motors usually come dual voltage. I would not go the expense of an additional piece of equipment (step-up transformer).

Re: Transformer help

Posted: Tue Jul 11, 2017 9:45 am
by gofaster
On 480v 3~ motors there is usually a diagram showing the pigtail configurations for different voltages. If there is not a diagram, an electric motor shop can reconfigure it for you. I had a motor on my milling machine that did not appear to have any pigtails to change it from 480v 3~ to 240v 3~. I took it to the local electrical shop and they pulled leads out somehow to make it work, and they only charged me a small fee. It was over 20 years ago and I'm a little bit fuzzy on the details. I'm still running my mill with the same motor.

Re: Transformer help

Posted: Fri Dec 08, 2017 8:22 pm
by SupStk
Realize this is an old post and you probably have the machine going by now. Going to suggest looking at a Siemens control. I know they are able to convert three from single phase. Think they also have a step up or down feature too. Hitachi makes a similar unit and may be others too. A buddy said he converted a machine that way and said the converter was cheap on Fleabay.

Re: Transformer help

Posted: Sun Dec 10, 2017 5:48 pm
by Schurkey
crazyman wrote:
Sat Apr 22, 2017 3:18 am
I've always considered having 3 phase installed if I ever build a house. Less $$ to run the A/C and well pump.
My power company told me they'd be happy to install 3-phase at my home.

$20,000 will get 'er done.

I said "No, thanks".